So…last night using OnAir to take a load from KRAP to ME16 about 1500 NM. Flight was great, no issues. Got the order from ATC to descend ultimately to 2700’ from FL 400. All the way through the descent I had no issues until I hit about 5000’ ( when I first noticed the problem). In the 10-15 seconds it took for me to select new altitude of 2700 from around 4800’ and to select my landing speed (in 787x btw) my trim had went from about 38% to 100% and despite having AP and auto throttle on i was losing altitude and speed FAST! Anti ice was on auto as per usual seeing as I had had no issues with it ever before. Seeing my pitch at max nose up, losing altitude and speed, I decided to deploy flap to 20 degrees (side note here, I I think there is a bug with 787x that you lose speed when going over flaps 20 even when at full power! not sure what that’s about) to try and level out trim and try to stop the altitude bleed. after a few seconds, I realized this was not helping so I decided to put max throttle…STILL losing speed and altitude. I then looked on outside of plane and saw ice. This was around midnight I could see there was ice but could not see if it was light or heavy. I then decided to switch anti ice to on. STILL no effect.
No matter what I did I could not regain control of the plane! Usually there is something to be learned from a crash…but in this case I have literally zero f’ing clue what happened to cause all this to transpire.
Back to the max flaps thing. A buddy of mine did not believe me, so he ended doing a full automated approach like I do (I don’t yet have any flight hardware) he too ended up having the issue where AP/AT would maintain speed until he went past flaps 20…Once he hit flaps 25 or 30, it was like the plane is uncapable of maintaining selected speed. Anyone else have this issue?